Ok, I already posted on audizine about this too. But I'm trying to get the most responses. Here is goes:

Ok Gentleman,
I figured I'd post this and see if anyone can help me identify these 2 sounds I"m hearing from my 2001 A4 1.8tq. They are incredibly annoying.

The first sound/vid is from what it looks like, the downpipe making the rattle, it sounds like a marble in a tin can. Is it the downpipe hitting the frame?

I recently bought the car in Feb. and it's had this sound ever since I've purchased the car (came with APR turbo-back exhaust). The sound tends to be not as loud, or doesn't make much of a sound once the engine is hot after a little drive. Also, it only makes this sound at idle.

Here's the vid for that:
http://www.davetech.net/~crichie/pics/Untitled.mpg

The next sound is a new one to me: Sounds like a heat shield or something obviously resonating. Thing is, it only does it once the engine warms up, and only on the drive. So sitting in the driveway with the clutch out, and reving it won't do anything. But after I came back home from a drive last night and pulled into the driveway, I kept the clutch pressed in, and was able to replicate the sound. Sound occurs at 2500 rpm - 3100 rpm. ONLY when the clutch is in.
Here's the sound:
http://www.davetech.net/~crichie/pics/sound2.wav

So as you can see, these are both VERY annoying. Help me out guys!

Thanks! Sorry for the long read.